beginners client server problem

I almost finished the online workshop but have some problems running multiplayer workshop 25.

I first check boxes client and server in: Options->Preferences
When I run the program (script25.c) I get the following errormessage:
"Malfunction W1527, start as client or server"

when I run the program again but then as a client, I do not get this message, however the client-server connection does not seem to be established. It looks like I'm running two clients instead of a client and a server.

Any one knows what went wrong???? I already checked my version and edition (7.8 commercial edition) so multiplayer should be supported.

i tried running script25_1.c with server adn client checked.
it runs i see red guard

then i run with client checked only, i see both guards and both are moving on both windows.

make sure you are running by clicking the middle run button.